Non-sliding vacuum gate valve

ABSTRACT

A non-sliding vacuum gate valve according to the present invention has a curved cam lead member provided to end of a valve rod, and a pair of rollers provided to a connection rod. The cam lead member and the rollers are engaged with each other and move relatively, so that vertical movement and slant movement of a valve plate and the valve rod are guided.

BACKGROUND OF THE INVENTION

The present invention relates to a non-sliding vacuum gate valve, andmore particularly to an improvement for reducing the number ofcomponents, and for attaining smooth action, simple structure and smallsize without using a spring member that forces a valve rod in apredetermined direction.

A structure of such a non-sliding vacuum gate valve used in the priorart is disclosed in Unexamined Japanese Patent Publication No. 7-83336,for example. The valve uses a set of inclined link and tension spring, aset of plate cam and tension spring, or a set of pin and cam hole, so asto prevent slant movement of a valve plate and a valve rod when they aremoving, and so that the valve plate and the valve rod are slanted afterthey have reached a predetermined position to close the opening of avalve box by the valve plate.

However, a conventional non-sliding vacuum gate valve as mentioned abovehas following disadvantages. First, the conventional valve has acomplicated structure since it requires a lot of components and a spacefor receiving the tension spring.

In addition, it is desirable for spring to be strong for secure action.In this case, reaction of the tension spring is strong, so that a highpower cylinder is needed.

Furthermore, in order to activate a mechanical lock, the cam plate orlink should be in the horizontal position. However, it is difficult tostart the opening action from this position, resulting in littlepossibility of a mechanical lock being used.

SUMMARY OF THE INVENTION

It is an object of the preset invention to provide a non-sliding vacuumgate valve that does not have a spring member forcing a valve rod in apredetermined direction and can reduce the number of components.

A non-sliding vacuum gate valve according to the present inventioncomprises a valve box having an opening, a valve plate that opens andcloses the opening, the valve plate being provided to a valve rod thatis moved and inclined by cylinders and a seal bellows provided to thevalve box, and a cam lead member and a pair of rollers provided betweenthe valve rod and a connection rod of the cylinders. The cam lead memberis disposed between the rollers, so that the movement of the cylindersis transmitted to the valve rod for the valve plate to open or to closethe opening.

As a concrete embodiment, the cam lead member is provided to the end ofthe valve rod and the rollers are provided to the connection rod of thecylinders.

Alternatively, the cam lead member is provided to the connection rod ofthe cylinders and the rollers are provided to the end of the valve rod.

Preferably, the cam lead member has a curved longitudinal protrudingportion.

More preferably, the cam lead member has cam lead surfaces consisting ofan arc surface and a continuous combination curve surface of plural arcssurfaces, which is a trace of a contact point with the rollers.

In another embodiment, the non-sliding vacuum gate valve furthercomprises a valve rod support member connected to the seal bellows formoving together with the valve rod, longitudinal guide rails disposed atthe inner side of the cylinders, rotation shafts provided to the end ofthe valve rod support member for engaging the longitudinal guide rails,narrow grooves provided to the longitudinal guide rails, so that outersurface and axial flat portions of the rotation shafts are engaged withthe narrow grooves.

Preferably, the cam lead surface of the cam lead member is provided witha lock position for locking the rollers, at which the valve plate closesthe opening.

More preferably, plural sets of the rollers are provided in the axialdirection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing of a non-sliding vacuum gate valveaccording to the present invention showing the opened valve state andthe closed valve state from side to side.

FIG. 2 is a schematic drawing of a principal part of the non-slidingvacuum gate valve shown in FIG. 1.

FIG. 3 is a side view of the non-sliding vacuum gate valve shown in FIG.1 showing the opened valve state.

FIG. 4 is a side view of the non-sliding vacuum gate valve shown in FIG.1 showing the closed valve state.

FIG. 5 is a side view of the non-sliding vacuum gate valve transferringfrom the opened valve state to the closed valve state.

FIG. 6 illustrates a cam lead member of the opened valve shown in FIG.3.

FIG. 7 is an overall schematic drawing of the opened valve shown in FIG.1.

FIGS. 8A-8E illustrate action of the valve sequentially from the openedvalve state to the closed valve state.

FIG. 9 is an exploded view of a principal part of the valve shown inFIG. 1.

FIGS. 10A-10C illustrate action of the principal part of the valve shownin FIG. 1.

FIGS. 11A-11C illustrate action of the principal part of another valveas a variation of the valve shown in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of a non-sliding vacuum gate valveaccording to the present invention will be described with reference tothe accompanying drawings.

FIG. 1 shows the valve in the opened state and the closed state fromside to side. In FIG. 1, reference numeral 1 denotes a valve box havingan opening 2 and a guide hole 3, through which a valve rod 4 penetrates.The valve rod 4 has a valve plate 5 that is disposed in the valve box 1.

The valve box 1 has an upper lid 6 and a lower lid 7 facing each other.The lower lid 7 is provided with a pair of air cylinders 8 and 9 havinga pair of guide rails 10 and 11 at the inner sides thereof. Each of theguide rails 10 and 11 has a longitudinal groove at the inner side andalong the longitudinal direction thereof. A narrow groove portion 50 anda wide groove portion 51 that is wider than the narrow groove portion 50are formed continuously from the lower side to the upper side of theguide rails 10 and 11, and a step portion 52 is formed at the wallportion.

The guide hole 3 provided to the lower lid 7 of the valve box 1 has aseal bellows 12 that is disposed at periphery of the valve rod 4 andcoaxially with the valve rod 4, and contacts closely with a portion ofthe guide hole 3. The lower end 12a of the seal bellows 12 is connectedto a valve rod support member 13 having a U-shaped section, which isdisposed at a periphery of the seal bellows 12.

The bottom portion of the valve rod support member 13 is connected tothe lower portion 4a of the valve rod 4, so that the guide hole 3 issealed with the seal bellows 12. The valve rod 4 is connected to a camlead member 14, which has an arc shape and a protruding longitudinalportion as shown in FIG. 2. A first cam lead surface 14a and a secondcam lead surface 14b are formed on both sides of the protrudinglongitudinal portion. The first cam lead surface 14a is a continuous arcsurface over the entire length, while the second cam lead surface 14b isa continuous combination curve surface of a convex surface and a concavesurface. In the upper portion of the second cam lead surface 14b, thereis point Q that is the lock position of a roller 20.

Cylinder pistons 15 and 16 of the cylinders 8 and 9 are connected witheach other via a connection rod 17. The middle portion of the connectionrod 17 is provided with a recess 18 corresponding to the cam lead member14. A first roller 19 and a second roller 20, which are attached to therecess 18 via a roller support member 18A, make sliding contact with thecam lead surfaces 14a and 14b, respectively. The cam lead member 14 isdisposed between the first and the second rollers 19 and 20. Two sets ofthe combination mechanism including the first and the second rollers 19and 20 are provided in the axial direction.

As shown in FIGS. 1 and 9, a pair of rotation shafts 21 and 22 isprovided to the upper portion of the valve rod support member 13,protruding horizontally in the outside direction. The rotation shafts 21and 22 move inside and along the narrow groove portions 50 of the guiderails 10 and 11, while flat portions 21b and 22b formed on the rotationshafts 21 and 22 in the axial direction engage the narrow grooveportions 50. Each of the rotation shafts 21 and 22 has a halfcircumference surface 21c and 22c.

The valve rod support member 13 has a pair of rectangular stoppers 25pivoted by the shaft 25A at the upper portion of the both outer sides ofthe valve rod support member 13. Each of the stoppers 25 is disposedinside the corresponding wide groove 51.

Each of the rotation shafts 21 and 22 can rotate as shown in FIG. 10Awhen the engagement with the narrow groove 50 is released. Though therotation shafts 21 and 22 have semicircle sections mentioned above, itis possible that they have rectangular sections as shown in FIGS.11A-11C to obtain the same effect.

Next, the action of the valve will be explained with reference to FIGS.3 to 8. First, in the state shown in FIGS. 8A and 3, the valve plate 5is opened, and the valve shaft 4 is retained not to drop downward sincethe cam lead member 14 engages the rollers 19 and 20. As shown in FIGS.8B and 5, when the cylinders 8 and 9 are activated to move the cylinderpiston 15 and 16 as well as the connection rod 17 upward toward theclosed valve state shown in FIG. 1, the valve plate 5 is moved upward tothe position corresponding to the opening 2 of the valve box 1, and therotation shafts 21 and 22 are moved upward along the guide rails 10 and11. The relationship between the cam lead member 14 and the rollers 19and 20 maintains substantially the same state as shown in FIG. 8A.

Next, as shown in FIG. 8C and 8D, when the connection rod 17 is movedupward by the cylinders 8 and 9, the rotation shafts 21 and 22 arereleased from the engagement with the narrow grooves 50 of the guiderails 10 and 11, and the rollers 19 and 20 move along the cam leadsurfaces 14a and 14b of the cam lead member 14. Then, the rotationshafts 21 and 22 rotate from the state shown in FIG. 10B to the stateshown in FIG. 10A, and the valve rod support member 13 and the valve rod4, which are integral with the rotation shafts 21 and 22, rotate (i.e.,slant) around the shaft 25A, so that an O-ring 5a of the valve plate 5contact tightly with the valve seat 2a of the opening 2.

Next, when the cylinders 8 and 9 are activated to move the connectionrod 17 upward, as shown in FIGS. 8E and 4, the rollers 19 and 20 areengaged securely with the point Q shown in FIG. 2 of the cam lead member14 and is locked. In this state, the O-ring 5a of the valve plate 5 isdeformed and is pressed to the valve seat 2a completely, so that theopening 2 is closed securely. In this condition, even if the activationof the cylinders 8 and 9 is stopped, the closed state of the valve plate5 is not influenced since the rollers 19 and 20 maintain the securelocked state with lock positions B and C.

In the above-mentioned closed valve state shown in FIG. 8E, a shiftangle θ of approximately three degrees is provided between the rotationcenter P of the second roller 20 of the first cam lead surface 14a andthe axis P1 of the second roller 20 in the locked state. By this shiftangle θ, the locked state is maintained securely.

Next, when opening the valve plate 5 from the above-mentioned closedstate, the cylinders 8 and 9 are moved downward. Then, the connectionrod 17 starts to move downward via the cylinder piston 15 and 16, andthe engagement of the rollers 19 and 20 with the cam lead member 14transfers from the state shown in FIG. 8E to the state shown in FIG. 8Acontrary to the above-mentioned direction. Thus, the valve plate 5 openscompletely separating from the valve seat 2a of the opening 2.Concerning the cam lead member 14 and the roller 19 and 20, the oppositearrangement is possible, in which the cam lead member 14 is attached tothe connection rod 17, and the rollers 19 and 20 are attached to thevalve rod support member 13.

The slant returning action and the vertical moving action are preferablyperformed independently of each other in the valve opening action.Therefore, movement separation of the shafts 21 and 22 as shown in FIGS.10A-10B is effective. This movement separation is necessary because ifthe two movements are performed simultaneously, the vertical movementstart before the O-ring 5a separates from the seal surface. In thiscase, since the O-ring 5a has to rub the seal surface, an accuratenon-sliding action cannot be realized, and particles can be generated.

The above-mentioned non-sliding vacuum gate valve according to thepresent invention has the following effects. The valve of the presentinvention does not use a spring that was necessary in the prior art forpreventing slant movement of a valve plate and a valve rod during theirmovements. The valve of the present invention also does not use a pinand a cam hole that was necessary for slant movement in the prior art.The valve of the present invention uses a pair of rollers, cam leadmembers and guide rails to attain a very smooth continuous action, andhas a more simple mechanism than in the prior art. Thus, cost reductionand down sizing of the valve can be performed.

What is claimed is:
 1. A non-sliding vacuum gate valve, comprising:avalve box having an opening; a valve plate that opens and closes theopening, the valve plate being attached to a valve rod that is moved andinclined by cylinders and seal bellows connected to the valve box; and acam lead member and a pair of rollers, situated between the valve rodand a connection rod of the cylinders, the cam lead member beingdisposed between rollers, where the rollers remain in contact with thecam lead member during the movement of the cylinders, so that themovement of the cylinders is transmitted to the valve rod for the valveplate to open or to close the opening.
 2. The non-sliding vacuum gatevalve according to claim 1, wherein the cam lead member is attached tothe end of the valve rod and the rollers are attached to the connectionrod of the cylinders.
 3. The non-sliding vacuum gate valve according toclaim 1, wherein the cam lead member is attached to the connection rodof the cylinders and the rollers are attached to the end of the valverod.
 4. The non-sliding vacuum gate valve according to claim 2, whereinthe cam lead member has a curved longitudinal protruding portion.
 5. Thenon-sliding vacuum gate valve according to claim 3, wherein the cam leadmember has a curved longitudinal protruding portion.
 6. The non-slidingvacuum gate valve according to claim 2, wherein the cam lead member hastwo cam lead surfaces consisting of a first surface with a continuousarc surface over the entire first surface and a second surface having aplurality of arcs surfaces, where each of the rollers makes contact withand traces one of the first and second surfaces.
 7. The non-slidingvacuum gate valve according to claim 3, wherein the cam lead member hastwo cam lead surfaces consisting of a first surface with a continuousarc surface over the entire first surface and a second surface having aplurality of arcs surfaces, where each of the rollers make contact withand traces one of the first and second surfaces.
 8. The non-slidingvacuum gate valve according to claim 4, wherein the cam lead member hastwo cam lead surfaces consisting of a first surface with a continuousarc surface over the entire first surface and a second surface havingplurality of arcs surfaces, where each of the rollers makes contact withand traces one of the first and second surfaces.
 9. The non-slidingvacuum gate valve according to claim 5, wherein the cam lead member hastwo cam lead surfaces consisting of a first surface with a continuousarc surface over the entire first surface and a second surface having aplurality of are arcs surfaces, where each of the rollers makes contactwith and traces one of the first and second surfaces.
 10. Thenon-sliding vacuum gate valve according to claim 1, further comprising avalve rod support member connected to the seal bellows for movingtogether with the valve rod, longitudinal guide rails disposed at theinner side of the cylinders, rotation shafts provided to the end of thevalve rod support member for engaging the longitudinal guide rails, therails having narrow grooves so that outer surface and axial flatportions of the rotation shafts are engaged with the narrow grooves. 11.The non-sliding vacuum gate valve according to claim 1, wherein the camlead surface of the cam lead member a lock position for locking therollers, at which the valve plate closes the opening.
 12. Thenon-sliding vacuum gate valve according to claim 11, wherein plural setsof the rollers are in an axial direction.